Cigarettes and other smoking articles contain a charge of tobacco which may be combusted to produce smoke which is inhaled by a user. Filters for smoking articles are used to modify the smoke resulting from the combustion of tobacco before it reaches the user's mouth. Filters known in the art for this purpose may be formed from a plug of fibrous cellulose acetate or other materials with similar physical properties. Cellulose acetate is known to absorb particulate smoke constituents in particular.
To enhance the removal of certain smoke constituents various additives may be added to smoking article filters. Examples include smoke adsorbents such as activated carbon which adsorbs certain smoke constituents thus removing them from the smoke stream passing through the filter.
In addition to removing constituents from smoke, filter additives may impart characteristics to smoke passing through the filter. For example, fragrances and flavourants may be incorporated which alter the aroma and taste characteristics of smoke that has passed through the filter.
Traditionally, smoking articles with filters incorporating the features described above are sold together in packs, with the smoking articles in each pack sharing the same flavours, fragrances and sorbent characteristics. As such, a user cannot customise his smoking articles to deliver a smoke profile to his choosing.